Reversed urban-rural differences in breast cancer mortality (China, 2002-2008)

The purpose of this study was to examine the urban-rural difference in breast cancer mortality between 2002 and 2008 in China. A longitudinal analysis of mortality data was performed. Mortality data were extracted from Chinese Health Statistics Yearbook. Linear regression was used to examine the statistical significance of linear trend in mortality rates. The percent change in rates was used to measure the linear trend, which was calculated as regression coefficient x 100 x 6 divided by the rate of 2002. Between 2002 and 2008, the mortality from breast cancer increased by 201% among urban women (P < 0.05) while among rural women the rate did not show the significant increase, thus resulting in a reversed urban-rural difference (from -2.3/100,000 population in 2002 to 3.6 in 2008). Subgroup analysis showed that the reversed urban-rural difference was completely due to substantial increases among urban women aged 55-59 years and aged 75 years and above. In addition, significant decreases of breast cancer mortality were observed in urban women aged 35-49 years and in rural women aged 35-39 years (P < 0.05). The reversed urban-rural difference in breast cancer mortality during 2002-2008 is primarily caused by the increases among elderly urban women. Further studies are needed to understand the increases and to develop cost-effective interventions for elderly urban women in China.